GEA Grasso - Servicing;Maintenance and Safety; Searching for Leaks on Refrigerant Side; Leak Test

OPERATING INSTRUCTIONS
CO
2
/NH
3
CASCADE UNIT
250 - 1000 KW
_551511_om_kas_gbr_1_.doc 41
every 24
Check weekly monthly Remarks
to 72hrs
Solenoid valves must switch audibly when the
output is adjusted. Check in operating mode "1
(manual + manual)“.
X
Output control
Number of operating
hours
Cf. maintenance schedule for necessary
maintenance/servicing work.
X
Oil pump collection
sump
X
Empty oil pump collection sump.
Oil collection sump
shaft seal
X
Empty oil collection sump shaft seal.
Visual inspections for leaks and replace ring
gaskets if necessary. See heat exchanger
documentation.
Heat exchanger
X
(for chillers only))
Before starting work on the CO
4.2 Servicing/maintenance and safety
2
circuit the
refrigerant must be completely removed by suction.
Caution!
When working on the CO
2
circuit ensure good
ventilation in the room, including in the area of the
floor.
The safety data sheets of the refrigerant
used and the refrigeration oils and in
particular the Grasso safety information
for the refrigerants NH
Contact with the refrigerant can cause cold burns or
frostbite.
(R717) and CO
3 2
(R744) are to be observed when working
on the CO
/NH
2 3
cascade.
Released gas can have a suffocating effect.
4.3 Searching for leaks on refrigerant side /
leak test
circuit
NH
3
Danger!
Prerequisite for perfect functioning of the cascade is
an absence of leaks in it.
All work on the NH
3
refrigerant circuit,
primarily opening, are significantly more
dangerous than the familiar safety
refrigerants!
Leaking parts or connection elements lead to
refrigerant and oil losses. The leaking point must
therefore be localized and repaired in the event of:
— Loss of inert gas charge (delivered condition)
Before starting work on the NH
3
circuit the
refrigerant must be completely removed by suction
and evacuation.
— Loss of the entire refrigerant charge or
— resulting undercharge
5
The most striking feature when leaks occur in the
filled NH
The pressure must then be equalized with the
environment by way of dry nitrogen. Only then can
the circuit be carefully opened or work performed
that could lead to unintentional opening of the
circuit.
3
refrigerant circuit is the pungent odour of
the refrigerant.
The odour threshold of ammonia concentrations in
air are far below the allowable maximum workplace
values (MAK values) and is very far removed from
Personnel protective equipment must be used if the
escape of even small amounts of ammonia cannot
be ruled out with certainty.
circuit
CO
5
see "charging characteristics" chapter
2